Medication delivery system with control valve

ABSTRACT

Valves and medication delivery systems including valves are described herein. A valve includes a valve body and a valve element. The valve body defines a first flow path, a second flow path, and a catheter flow path. The valve element is disposed within the valve body, wherein the valve element is configured to permit fluid communication between the first flow path and the second flow path in a priming position, and is configured to permit fluid communication between the first flow path and the catheter flow path in a dispensing position.

REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser. No. 16/403,403, filed May 3, 2019, the entire disclosure of which application being incorporated herein by this reference.

FIELD OF THE INVENTION

The present disclosure generally relates to medication delivery systems, and, in particular, to valves.

BACKGROUND

Medical treatments often include the infusion of a medical fluid (e.g., a saline solution or a liquid medication) to patients using an intravenous (IV) catheter that is connected though an arrangement of flexible tubing and fittings, commonly referred to as an “IV set,” to a source of fluid, for example, a syringe. Certain configurations of IV sets may have extended lengths of tubing, for example, in excess of 6 feet. Additionally, tubing may be primed with saline prior to the infusion of a liquid medication.

In some applications, during the use of IV catheters, saline from the priming process may be delivered to patient before the liquid medication is delivered to the patient.

SUMMARY

The disclosed subject matter relates to valve. In certain embodiments, a valve is disclosed that comprises a valve body defining a first flow path, a second flow path, and a catheter flow path; and a valve element disposed within the valve body, wherein the valve element is configured to permit fluid communication between the first flow path and the second flow path in a priming position, and is configured to permit fluid communication between the first flow path and the catheter flow path in a dispensing position.

In certain embodiments, a medication delivery system is disclosed that comprises a syringe, comprising: a syringe body defining a syringe cavity; a first plunger disposed within the syringe cavity and defining a first chamber in the syringe cavity; a second plunger disposed within the syringe cavity, the second plunger defining a second chamber in the syringe cavity; and a valve, comprising: a valve body defining a first valve flow path in fluid communication with the first chamber, a second valve flow path in fluid communication with the second chamber, and a catheter flow path in fluid communication with a catheter; and a valve element disposed within the valve body, wherein the valve element is configured to permit fluid communication between the first chamber and the second chamber in a priming position, and is configured to permit fluid communication between the first chamber and the catheter flow path in a dispensing position.

In certain embodiments, a method to deliver medication is disclosed that comprises introducing saline into a medication flow path; and directing saline from the medication flow path to a return flow path via a valve element; and introducing medication into the medication flow path; actuating the valve element to permit fluid communication between the medication flow path and a catheter; and directing medication from the medication flow path into the catheter.

It is understood that various configurations of the subject technology will become readily apparent to those skilled in the art from the disclosure, wherein various configurations of the subject technology are shown and described by way of illustration. As will be realized, the subject technology is capable of other and different configurations and its several details are capable of modification in various other respects, all without departing from the scope of the subject technology. Accordingly, the summary, drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed embodiments and together with the description serve to explain the principles of the disclosed embodiments. In the drawings:

FIGS. 1, 1A, and 1B are a perspective view of a medication delivery system 100 and a cross-sectional view of a portion of the medication delivery system 100, in accordance with various aspects of the present disclosure.

FIG. 2 is a perspective view of the medication delivery system of FIG. 1 with the priming trigger removed, in accordance with various aspects of the present disclosure.

FIG. 3 is a perspective view of the medication delivery system of FIG. 1 with the syringe actuated, in accordance with various aspects of the present disclosure.

FIG. 4 is a perspective view of the medication delivery system of FIG. 1 with the syringe actuated, in accordance with various aspects of the present disclosure.

FIG. 5 is an elevation view of a syringe with the syringe body hidden, in accordance with various aspects of the present disclosure.

FIG. 6 is an elevation view of the syringe of FIG. 5 with the syringe body hidden and the priming trigger removed, in accordance with various aspects of the present disclosure.

FIG. 7 is an elevation view of the syringe of FIG. 5 with the syringe body hidden and the priming mechanism actuated, in accordance with various aspects of the present disclosure.

FIG. 8 is an elevation view of the syringe of FIG. 5 with the syringe body hidden and the syringe actuated, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

The disclosed valve incorporates a valve element to direct flow for priming and dispensing medical fluids. Fluid can flow from the first flow path to a second flow path in a priming configuration and from a first flow path to a catheter flow path in a dispensing position. By controlling fluid flow through the valve, medication can be administered without dispensing excess medical fluids.

The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be apparent to those skilled in the art that the subject technology may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. Like components are labeled with identical element numbers for ease of understanding. Reference numbers may have letter suffixes appended to indicate separate instances of a common element while being referred to generically by the same number without a suffix letter.

While the following description is directed to the administration of medical fluid using the disclosed valve, it is to be understood that this description is only an example of usage and does not limit the scope of the claims. Various aspects of the disclosed valve may be used in any application where it is desirable to control the flow of medical fluids.

The disclosed valve overcomes several challenges discovered with respect to certain conventional medication delivery systems. One challenge with certain conventional delivery systems is that systems may deliver excess medical fluid, such as saline, to patients. Because excess medical fluid may delay the delivery of medical fluids and may not be tolerated by fluid restricted patients, such as premature babies the use conventional medication delivery systems is undesirable.

Therefore, in accordance with the present disclosure, it is advantageous to provide a valve as described herein that eliminates or substantially reduces delivering excess medical fluid to a patient. The disclosed valve provides a valve element that permits dispensing medical fluids while minimizing excess fluid delivered to a patient.

An example of a valve that prevents delivery of excess medical fluid is now described.

FIGS. 1 and 1A are a perspective view of a medication delivery system 100 and a cross-sectional view of a portion of the medication delivery system 100, in accordance with various aspects of the present disclosure. In the illustrated example, the medication delivery system 100 delivers medication from the syringe 130 to the patient via a catheter 112 without delivering excess fluid, such as saline, used to prime the medication delivery system 100.

In some embodiments, a medication flow path within a dual lumen tubing 120 can be primed with saline to remove any air or trapped gasses within the medication flow path of the dual lumen tubing 120. Saline can be advanced from a proximal end 132 of the syringe 130, through the medication flow path of the dual lumen tubing 120 and to the valve 110.

The saline from the medication flow path 120 a of the dual lumen tubing 120 can be received by the medication flow path 111 of the valve 110. As shown in FIG. 1A in a priming configuration, a valve element 113 can prevent saline from the medication flow path 111 from entering the patient catheter 112 and can instead direct the saline toward the return flow path 109 of the valve 110 to allow primed saline to be returned to the syringe 130 via the return flow path 120 b of the dual lumen tubing 120.

FIG. 2 is a perspective view of the medication delivery system 100 of FIG. 1 with the priming trigger 180 removed, in accordance with various aspects of the present disclosure. In the illustrated example, the syringe 130 advances medication within the medication flow path of the dual lumen tubing 120 to prime the medication flow path of the dual lumen tubing 120. Advantageously, by priming the medication flow path with medication, the medication can be delivered to the patient via the catheter 112 proximal to the patient with less delay and without delivering the saline used to prime the medication flow path of the dual lumen tubing 120.

To introduce medication into the medication flow path of the dual lumen tubing 120, the medication plunger within the syringe 130 can be advanced or otherwise displaced to introduce a volume of medication into the medication flow path of the dual lumen tubing 120. Optionally, the medication plunger of the syringe 130 can be configured to be advanced or displaced a desired amount to dispense a volume of medication into the medication flow path of the dual lumen tubing 120 that is equivalent to the volume of the medication flow path of the dual lumen tubing 120. In other words, medication plunger of the syringe 130 can be advanced to fill the volume of the medication flow path of the dual lumen tubing 120 up to the valve element 113 to prime the medication for administration via the catheter 112.

In some embodiments, the priming of medication into the medication flow path of the dual lumen tubing 120 can be automated or otherwise simplified. For example, the medication plunger can be biased to be advanced to introduce medication into the medication flow path of the dual lumen tubing 120. The biasing member of the priming mechanism within the syringe 130 can be released by removing the priming trigger 180. By removing the priming trigger 180, the biasing member can advance the medication plunger to prime the medication within the medication delivery system 100. Optionally, the priming travel of the medication plunger can be stopped or limited by a priming stop 182. By limiting the travel of the medication plunger during priming, a desired volume of medication can be introduced into the medication flow path of the dual lumen tubing 120, for example, sufficient medication volume to fill the medication flow path of the dual lumen tubing 120.

As illustrated, as the medication is introduced into the medication flow path of the dual lumen tubing 120, the saline previously primed through the dual lumen tubing 120 is displaced. The displaced saline is directed by the valve element 113 through the return flow path 109 of the valve 110 and into the return flow path of the dual lumen tubing 120.

Medical fluid from the return flow path of the dual lumen tubing 120 can be returned into the syringe 130. Returned medical fluid such as saline can be introduced into a return or saline chamber of the syringe 130.

FIG. 3 is a perspective view of the medication delivery system 100 of FIG. 1 with the syringe 130 actuated, in accordance with various aspects of the present disclosure. In the illustrated example, the syringe 130 is actuated to dispense medication to the patient through the catheter 112.

As illustrated, the distal end 134 of the syringe 130 can be advanced toward the proximal end 132 of the syringe 130 to actuate the medication plunger within the syringe 130. By actuating the syringe 130, the medication plunger can be advanced to deliver medication from the syringe 130 into the medication flow path of the dual lumen tubing 120. In some embodiments, the syringe 130 can be actuated by a syringe pump to control the flow of medication to the patient.

During operation, the valve 110 is actuated to permit the flow of medication from the medication flow path 111 of the valve 110 to the patient via the catheter 112. In some embodiments, the valve element 113 is actuated to permit fluid communication between the medication flow path 111 and the catheter 112 to allow medication to flow to the patient (as shown in FIG. 1B). Optionally, the valve 110 can be located proximal to the patient to minimize the length of the catheter 112, reduce the amount of saline administered to the patient, and reduce the delivery time for the medication.

In some embodiments, the position of the valve element 113 can be actuated between directing flow between the medication flow path 111 and the return flow path 109 (priming position, FIG. 1A) and directing flow between the medication flow path 111 and the catheter 112 (dispensing position, FIG. 1B) by physically manipulating the valve 110. For example, the valve 110 can be actuated or manipulated to actuate the valve element 113 by twisting, pushing, displacing, or otherwise actuating the valve 110. In some embodiments, the valve element 113 can be actuated by pressure signals or impulses received by the valve element 113 from within the medication flow path 111 and/or the return flow path 109. For example, the valve element 113 can be actuated from a priming position to a dispensing position by receiving a pressure impulse in the medication flow path 111 and/or the return flow path 109.

In some embodiments, the valve 110 can be an anti-siphon valve. Optionally, the valve 110 may have a high “cracking pressure” wherein if sufficient pressure is applied to the valve element 113, the valve element 113 can move from a priming position to the dispensing position. For example, the valve element 113 can be actuated from a priming position to a dispensing position by receiving an equalized pressure in both the medication flow path 111 and the return flow path 109. The syringe 130 may provide a suitable pressure signal.

FIG. 4 is a perspective view of the medication delivery system 100 of FIG. 1 with the syringe 130 actuated, in accordance with various aspects of the present disclosure. In the illustrated example, the syringe 130 advances saline through the medication flow path of the dual lumen tubing 120 to advance the remaining medication to the patient via the catheter 112.

As illustrated, after the medication is expelled from the syringe 130, medication may remain in the volume of the medication flow path of the dual lumen tubing 120. To ensure that the medication is fully delivered to the patient, the syringe 130 can be utilized to administer a saline “push” to continue to advance the medication through the medication flow path of the dual lumen tubing 120 after the medication within the syringe 130 is exhausted. Optionally, saline can be administered through the medication flow path until the medication is fully administered to the patient.

FIG. 5 is an elevation view of a syringe 230 with the syringe body hidden, in accordance with various aspects of the present disclosure. In the figures, similar features may be referred to with similar reference numerals. In the depicted example, the syringe 230 can be utilized to dispense medication and/or saline through a tubing coupled to the syringe port 229 of the syringe 230. As illustrated, the syringe 230 can receive, store, and/or dispense medication and/or saline in chambers defined therein.

As illustrated, the proximal syringe portion 231 of the syringe 230 can store medical fluids such as medication and saline in a syringe cavity 236. In the illustrated embodiment, the medication plunger 240 is movable within the syringe cavity 236 to define a medication chamber 242 within the proximal syringe portion 231. Optionally, the volume of the medication chamber 242 is defined by the position of the medication plunger 240 relative to the proximal end 232 of the syringe 230. In the depicted example, the medication chamber 242 can store medication.

In some embodiments, the medication chamber 242 is in fluid communication with the syringe port 229 of the syringe 230. Optionally, the medication plunger 240 can include one or more seals 244 to seal against the walls of the syringe cavity 236 to prevent unintended fluid migration or mixing.

Further, the medication plunger 240 can be moved by the medication plunger shaft 246. In some embodiments, the medication plunger 240 can be drawn distally to expand the medication chamber 242 and draw in more medication or medical fluid through the syringe port 229. In some embodiments, the medication plunger 240 can be advanced proximally to contract the medication chamber 242 and expel medication or medical fluid from the medication chamber 242 through the syringe port 229.

In the illustrated embodiment, the saline plunger 250 is movable within the syringe cavity 236 to define a saline chamber 252 within the proximal syringe portion 231. In some embodiments, the saline plunger 250 and the medication plunger 240 cooperatively define the saline chamber 252 within the syringe cavity 236. Optionally, the volume of the saline chamber 252 is defined by the position of the medication plunger 240 and the saline plunger 250. In the depicted example, the saline chamber 252 can store saline or other medical fluids.

Optionally, the saline plunger 250 can include one or more seals 254 to seal against the walls of the syringe cavity 236 to prevent unintended fluid migration or mixing.

Further, the saline plunger 250 can be moved by the saline plunger shaft 256. In some embodiments, the saline plunger 250 can be drawn distally to expand the saline chamber 252 and draw in more saline or medical fluid. In some embodiments, the saline plunger 250 can be advanced proximally to contract the saline chamber 252 and expel saline or medical fluid from the saline chamber 252.

As previously described, during the administration of medication to patients, for example, fluid restricted patients, medication can be dispensed from the medication chamber 242 and then saline can be dispensed from the saline chamber 252 to advance the medication remaining in the tubing.

In the depicted example, medication can be dispensed from the syringe 230 by advancing the medication plunger 240 within the syringe cavity 236. As a result, medication can be delivered from the syringe 230 through the syringe port 229.

In some embodiments, the syringe 230 can include a priming mechanism or actuation mechanism 270 to automate, control, or otherwise simplify advancement of the medication plunger 240 to facilitate the priming of medication into an IV tubing. Optionally, the actuation mechanism 270 can be configured to introduce a sufficient volume of medication from the medication chamber 242 into the IV tubing to fully fill or prime the IV line prior to administration of the medication to the patient.

In the illustrated embodiment, the actuation mechanism 270 can utilize a biasing member such as a tension spring 274 to advance the medication plunger 240 within the syringe cavity 236.

Optionally, the tension spring 274 can be coupled to the proximal syringe portion 231 at the proximal end 276 of the tension spring 274 and coupled to the actuation mechanism 270 at the distal end 275 of the tension spring 274. In some embodiments, the actuation mechanism 270 extends from, or is generally coupled to the medication plunger shaft 246. Further, the tension spring 274 can be disposed around the medication plunger shaft 246.

As illustrated, the tension spring 274 can be preloaded or biased to facilitate advancement of the medication plunger 240 upon release or activation of the tension spring 274. In the depicted example, the tension spring 274 can be extended or biased from a resting length to an elongated tensioned length. In some embodiments, a biasing member can be compressed from a resting length to a shortened compressed length.

As illustrated, the tension spring 274 can be preloaded or elongated by retracting the actuation mechanism 270, which extends the tension spring 274. In some embodiments, the actuation mechanism 270 can be locked or retained in place, preventing the medication plunger 240 from being advanced prior to priming by a retention mechanism. In the illustrated embodiment, the retention mechanism includes a priming trigger 280 with a shaft 282 that extends through the distal syringe portion 233 and through the through hole 272 of the actuation mechanism 270, releasably coupling the actuation mechanism 270 to the distal syringe portion 233. The priming trigger 280 can extend through slot 284 of the distal syringe portion 233.

Optionally, the tension applied to the tension spring 274 can be adjusted by altering the position of the actuation mechanism 270 relative to the distal syringe portion 233 and inserting the priming trigger 280 through a slot 284 aligned with the through hole 272 of the actuation mechanism 270.

FIG. 6 is an elevation view of the syringe 230 of FIG. 5 with the syringe body hidden and the priming trigger 280 removed, in accordance with various aspects of the present disclosure. As illustrated, the priming mechanism of the syringe 230 can be activated by removing the priming trigger 280 from the syringe 230.

By removing the priming trigger 280, the tension spring 274 is allowed to contract to advance the medication plunger shaft 246 and in turn, the medication plunger 240. By advancing the medication plunger 240, medication within the medication chamber 242 can advance through the IV tubing and prime the IV tubing. As described herein, the medication plunger 240 can be advanced by a desired or predetermined amount corresponding to the IV tubing volume during the priming process.

FIG. 7 is an elevation view of the syringe 230 of FIG. 5 with the syringe body hidden and the priming mechanism actuated, in accordance with various aspects of the present disclosure. In the illustrated embodiment, the medication plunger 240 can be further actuated to administer any remaining medication in the medication chamber 242 into the IV tubing and to the patient. In some embodiments, the medication plunger shaft 246 can be actuated to advance the medication plunger 240. For example, the distal end 234 of the distal syringe portion 233 can be advanced toward the proximal end 232 to advance the medication plunger 240. In some embodiments, the extensions 238 of the proximal syringe portion 231 can allow a clinician or a syringe pump to advance the distal syringe portion 233 relative to the proximal syringe portion 231.

FIG. 8 is an elevation view of the syringe 230 of FIG. 5 with the syringe body hidden and the syringe actuated, in accordance with various aspects of the present disclosure. In the illustrated embodiment, the saline plunger 250 can be actuated to administer saline from the saline chamber 252 into the IV tubing to “push” or deliver any remaining medication in the IV tubing to the patient. In some embodiments, the saline plunger shaft 256 can be actuated to advance the saline plunger 250. In some embodiments, the same actuation method for the medication plunger 240 can be utilized for actuating the saline plunger 250.

For example, the distal end 234 of the distal syringe portion 233 can be advanced toward the proximal end 232 to advance the saline plunger 250. In some embodiments, the extensions 238 of the proximal syringe portion 231 can allow a clinician or a syringe pump to advance the distal syringe portion 233 relative to the proximal syringe portion 231.

In some embodiments, saline from the saline chamber 252 can be advanced through or around the medication chamber 242 to exit the syringe 230 via the syringe port 229.

The present disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. The disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects.

A reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention.

The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. In one aspect, various alternative configurations and operations described herein may be considered to be at least equivalent.

A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples. A phrase such an embodiment may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples. A phrase such a configuration may refer to one or more configurations and vice versa.

In one aspect, unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. In one aspect, they are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

In one aspect, the term “coupled” or the like may refer to being directly coupled. In another aspect, the term “coupled” or the like may refer to being indirectly coupled.

Terms such as “top,” “bottom,” “front,” “rear” and the like if used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference.

Various items may be arranged differently (e.g., arranged in a different order, or partitioned in a different way) all without departing from the scope of the subject technology. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim.

The Title, Background, Summary, Brief Description of the Drawings and Abstract of the disclosure are hereby incorporated into the disclosure and are provided as illustrative examples of the disclosure, not as restrictive descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the Detailed Description, it can be seen that the description provides illustrative examples and the various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects described herein, but is to be accorded the full scope consistent with the language claims and to encompass all legal equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of 35 U.S.C. § 101, 102, or 103, nor should they be interpreted in such a way. 

What is claimed is:
 1. A method to deliver medication, the method comprising: introducing saline into a medication flow path; and directing saline from the medication flow path to a return flow path via a valve element; and introducing medication into the medication flow path; actuating the valve element to permit fluid communication between the medication flow path and a catheter; and directing medication from the medication flow path into the catheter.
 2. The method of claim 1, further comprising pressurizing the medication flow path and the return flow path to actuate the valve element to permit fluid communication between the medication flow path and the catheter.
 3. The method of claim 1, further comprising actuating a portion of a valve body to actuate the valve element to permit fluid communication between the medication flow path and the catheter.
 4. The method of claim 1, further comprising providing a pressure impulse in the medication flow path to actuate the valve element to permit fluid communication between the medication flow path and the catheter.
 5. The method of claim 1, further comprising providing a pressure impulse in the return flow path to actuate the valve element to permit fluid communication between the medication flow path and the catheter.
 6. The method of claim 1, further comprising introducing saline into the medication flow path to advance medication within the medication flow path.
 7. The method of claim 1, further comprising introducing medication from a first chamber of a syringe into the medication flow path.
 8. The method of claim 1, further comprising introducing saline from the return flow path into a second chamber of a syringe.
 9. The method of claim 1, further comprising introducing saline into the medication flow path via a syringe.
 10. The method of claim 9, further comprising introducing saline into the medication flow path via a saline chamber of the syringe.
 11. The method of claim 10, further comprising advancing a saline plunger defining the saline chamber to introduce the saline into the medication flow path.
 12. The method of claim 10, further comprising introducing medication into the medication flow path via a medication chamber of the syringe.
 13. The method of claim 12, further comprising advancing a medication plunger defining the medication chamber to introduce the medication into the medication flow path.
 14. The method of claim 12, further comprising permitting fluid communication between the saline chamber and the medication flow path via a tubing.
 15. The method of claim 12, further comprising permitting fluid communication between the medication chamber and the medication flow path via a tubing.
 16. The method of claim 14, wherein the tubing is longer than the catheter. 